import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int minimumNumber(int n, String password)
    {
       char[] ch=password.toCharArray();
       int count1=0;
       int count2=0;
       int count3=0;
        int count4=0;
        
        
            for(int i=0;i<n;i++)
            {
                if((int)ch[i]>64 && (int)ch[i]<91)
                    count1++;
                if((int)ch[i]>96 && (int)ch[i]<122)
                    count2++;
                if(ch[i]=='!' || ch[i]=='@'|| ch[i]=='#' ||ch[i]=='$' ||ch[i]=='%'||ch[i]=='^'||ch[i]=='&'||ch[i]=='*'||ch[i]=='('||ch[i]==')'||ch[i]=='-'||ch[i]=='+')
                    count3++;
            }
        
        if(count1>0 &&count2>0 && count3>0)
            return 0
            else if(count1=0 && count2>0 &&count3>0)
                return 1;
           else if(count1=0 && count2=0 &&count3>0)
               return 2;
           else (count1=0 && count2=0 &&count3=0)
               return 3;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
}